Diesters of 1,3-bis(carboxymethyl)adamantanes and process for preparing same

ABSTRACT

1. A COMPOUND OF THE FORMULA   1,3-DI(R-OOC-CH2-),5,7-DI(R&#39;&#39;)-ADAMANTANE   WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF CROTYL, OLEYL, LIOLEYL AND METHALLYL, AND R&#39;&#39; IS H OR ALKYL HAVING 1 TO 4 CARBON ATOMS.

United States Patent US. Cl. 260468 G 2 Claims ABSTRACT OF THE DISCLOSURE A compound of the formula ca cooa wherein R is selected from the group of hydrocarbon radicals having 4 to 20 carbon atoms consisting of (a) linear and branched-chain alkyls and alkenyls, and (b) monocyclic and polycyclic cycloalkyls and cycloalkenyls; and R is H or alkyl having 1 to 4 carbon atoms. The compound is prepared by reacting l,3-bis(carboxymethyl)adamantane, or its 5,7-alkyl derivatives, with a monohydric alcohol (ROH) in the presence of esterification catalyst. The compounds are useful as oiling agents for synthetic fibers and as synthetic lubricating oil bases.

BACKGROUND OF THE INVENTION Field of the Invention This invention relates to diesters of l,3-bis(carboxymethyladamantanes and a process for preparing same. More precisely, it relates to a process for preparing diesters of 1,3-bis(carboxymethyl)adamantane with higher alcohols having from 4 to 20 carbon atoms.

Description of the Prior Art Among the diesters of l,3-bis(carboxymethyl)adamantane and related compounds, there have been synthesized only a few diesters such as 1,3-bis(methoxycarbonylmethyl)adamantane, and 5,7-dimethyl-l,3-bis(methoxycarbonylmethyl)adamantane (K. Bott; Chem. Ber., 564 (1968)), and there have not been known hitherto any diesters of higher alcohols having a carbon atom number of 4 or more.

SUMMARY OF THE INVENTION A compound according to the invention has the formula l CH CQOR wherein R is selected from the group of univalent hydrocarbon radicals having 4 to 20 carbon atoms consisting of (a) linear and branched-chain alkyls and alkenyls, and (b) monocyclic and polycyclic cycloalkyls and cycloalkenyls; and R is H or alkyl having 1 to 4 carbon atoms.

The present inventors found that l,3-bis(carboxymethyl)adamantane and its derivatives with alkyl substituents in the adamantane ring can be esterified readily with higher alcohols. The present invention provides a process for manufacturing diesters of 1,3-bis(carboxyrnethyl)adamantane or its ring-substituted alkyl derivatives by esterifying the said adamantane compound with a monohydric alcohol having from 4 to 20 carbon atoms selected from the group consisting of aliphatic alkanols and alkenols with a linear or branched structure and cycloaliphatic alkanols and alkenols with monoor poly-cyclic structure and in the presence of acidic, neutral or alkaline catalyst. The diesters of l,3-bis(carboxymethyl)adamantane compounds thus obtained are novel substances that have not been synthesized before.

As these novel diesters have high heat stabilities and many other unsual properties that are not seen in ordinary aliphatic esters, e.g., low viscosities and high viscosity indiees, which are the result of the presence of the adamantane ring, they are very useful, for instance, as oiling agents for synthetic fibers and synthetic lubricating oil bases, particularly for aviation engines.

The products of this invention are obtained by heating and dehydrating a mixture of 1,3-bis(carboxymethyl)ada mantane, or its ring-substituted alkyl derivatives, and one of the above-described alcohols, in the presence of the catalyst. The reactivities of the two carbonyl groups in the l,3-bis(carboxymethyl)adamantane compounds in the said esterification reactions are the same, thus indicating that the two carboxyl groups are separated far enough to be electronically as Well as sterically independent of each other. Therefore, it is unnecessary to provide different reaction conditions between the first and the second esterifications, and diesterification can be carried out smoothly in one and the same reaction. Moreover, the presence of alkyl substituents in the adamantane ring does not affect the reactivity of the carboxyl groups, and, therefore the reaction conditions do not need to be altered substantially, depending on the presence or absence of alkyl substituents in the adamantane ring.

The catalyst which can be used effectively for the esterification reaction of this invention includes all the substances that are known as so-called esterification catalysts, for example, acid catalysts such as sulfuric acid, aliphatic and aromatic sulfonic acids, and boron trifiuoride, and neutral or alkaline catalysts such as oxides or hydroxides of alkali metals, alkali earth metals, zinc, cadmium, tin, lead, antimony and bismuth. As ring-substituted alkyl derivatives of 1,3-bis(carboXymethyDadamantane, there are exemplified 5-methyl-, 5,7-dimethyl-, 5- methyl-7-ethyl-, and S-ethyl-substituted adamantanes. As higher alcohols having a carbon atom number of from 4 to 20, there are exemplified linear alkanols such as nbutyl alcohol, n-amyl alcohol, n-hexyl alcohol, n-octyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol, branched alkanols such as i-butyl alcohol, i-amyl alcohol, Z-ethylhexanol-l, and 2-methyldodecanol-l, linear alkenols such as crotyl alcohol, oleyl alcohol and linoleyl alcohol, branched alkenols such as methallyl alcohol, monocyclic saturated alcohols such as cyclohexanol, methylcyclohexanols, and cyclohexylcarbinol, monocyclic unsaturated alcohols such as 2-cyclohexenol, polycyclic saturated alcohols such as Z-decalol, 1- hydroxyadamantane, and 2-exo-hydroxy exo trirnethylenenorbornane, and polycyclic unsaturated alcohols such as 2-ex0-hydroxy-2,3-dihydr0-ex0-dicycl0pentadiene.

In carrying out the esterification reaction according to the present invention, it is generally advantageous to use either said dicarboxylic acid component (1,3-bis(carboxylmethyl)adamantane) or said alcohol component in excess from the viewpoint of obtaining a shorter reaction time, but the reaction can be of course completed smoothly with the use of substantially stoichiometric amounts of each component. The amount of the catalyst used for this esterification reaction is in the range of 0.0002-0.2 mol, preferably 0.001-0.01 .mol for each mol of the dicarboxylic acid component. When the adequate kind and amount of catalyst is selected and used as described above, the esterification reaction of this invention can be completed within 15 hours. The reaction temperature in this reaction is not substantially different from those used in the esterification of aliphatic carboxylic acids generally; that is, the temperature is in the range from 30 to 300 C., preferably from 50 to 260 C. To remove the water produced in the esterification reaction out of the reaction system, there may be employed any known means such as distillation under atmospheric or reduced pressure, removal by passing an inert gas through the reaction mixture, and removal by an azeotropic distillation. But it is most convenient to carry out azeotropic distillation using cyclohexane, benzene, toluene, or xylene, considering the highly sublimable property of the adamantane compounds. Indeed the loss of adamantane compounds due to sublimation causes a major problem when an excess of adamantane acids is used to esterify high boiling point alcohols.

The sublimation of adamantane acids can be prevented very effectively by the use of these azeotropic agents.

Examples of this invention are illustrated below, in which the melting points and boiling points are not corrected and parts are by weight, unless otherwise noted.

EXAMPLE 1 Preparation of 1,3-bis(n-butoxycarbonylmethyl) adamantane (I) In a reaction flask fitted with a side tube where the water-butanol mixture running down from the reflux condenser is settled and where the water layer thus formed is separated and removed, there was added a mixture of 12.6 parts of 1,3-bis(carboxymethyl)adamantane, 37.1 parts of n-butyl alcohol, and 1.22 parts of p-toluene sultonic acid crystal. The mixture was heated under reflux with stirring for 12 hours while separating the water pro duced.

After the reaction mixture was allowed to cool, 100 parts by volume of benzene were added, and the mixture was washed successively twice, each time with 100 parts by volume of water, then washed with a saturated aqueous solution of sodium bicarbonate until the washing became alkaline, and finally with water. The benzene solution was then dried with anhydrous sodium sulfate, and then was fractionated. The fraction and boiling at 163-170 C. (0.2 mm.) was collected to obtain 137 parts of I, a olorless liquid, n 1.4815. The yield was 75%. z

Analysis.Found: C, 72.2; H, 9.8; O, 17.2%. Calculated for C H O C, 72.49; H, 9.96; O, 17.56%.

IR spectrum (liquid film, cm."

1730 (vs): 11 ester 1250 (s), 1135 (s): v,,,, ester 740 (W): p-(CH n-butyl.

NMR spectrum (CCl, solution, TMS as internal standard, 'r):

6.00 (t, J=6 H 4H):

COO

8.97 (s, 7H): adamantane tertiary H and 4 815-89 (complex m, 20H): adamantane secondary H and 9.04 (t, i=6 H 6H):

Mass spectrum (m/e, relative intensity): 364 (10.0) (parent peak), 309 (11.6), 291 (18.7), 262 (18.4), 249 (100.0), 206 (24.3), 192 (81.8), 175 (25.0), 169 (12.2), 162 (11.4), l47(27.9), 133 (46.2).

EXAMPLE 2 Preparation of 1,3-bis(2-ethylhexyloxycarbonylmethyl) adamantane (II) In the same apparatus used in Example 1, a mixture consisting of 12.6 parts of l,3-bis(carboxymethyl)adamantane, 14.3 parts of 2-ethylhexanol and 0.08 part of zinc oxide was heated at 200-210 C. A small amount of xylene was added from time to time to maintain the reflux and stirring was continued for 6 hours. The total added amount of xylene was 4.5 parts by volume, and the volume of the water layer distilled out toward the end of the reaction was 1.6 part by volume. Then, to the reaction mixture were added parts by volume of xylene and the xylene solution was washed and dried as described in Example 1, and then a low-boiling fraction was distilled off under reduced pressure (0.5 mm.; the temperature, not exceeding C.). There were obtained 19.6 parts of a viscous, pale yellow liquid of II as the distillation residue (yield=83%). 11 1.4830.

Saponification value: Found, 231.9; calculated, 235.4.

Acid value: Found, 1.8; calculated, 0.

Acetyl value: Observed, 0.2; calculated, 0.

Analysis.-Found: C, 75.1; H, 10.7%. Calculated for (33 115204: C, H,

IR spectrum (liquid film, cmr

1730 (s): 1 ester 1250 (s), 1130 (s): v,,,, ester.

NMR spectrum (CCL, solution, TMS as internal standard, -r):

6.02 (d, i=5 H 4H):

C O OCH: CH/ L 7.93 (undissolved resonance, 6H): adamantane tertiary H and 8.1-8.9 (undissolved resonance, 30H): adamantane secondary H and other alkyl H Mass sectrum (m/e, relative intensity): 476 (2.3) (parent peak), 365 (5.3), 347 (3.3), 305 (33), 253 (50), 235 (100).

EXAMPLE 3 Preparation of l,3-bis(lauryloxycarbonylmethyl) w adamantane (III) In the same apparatus used in Example 1, a mixture of 12.6 parts of l,3-bis(carboxymethyl)adamantane, 20.5 parts of lauryl alcohol, 0.14 part of anhydrous sodium carbonate and 9 parts by volume of xylene was refluxed for 6 hours while the reaction temperature was kept between 200 and 210 C. At the end of the reaction the distilled water amounted to 2.0 parts by volume.

Then, after adding 100 parts by volume of xylene to the cooled reaction mixture, the xylene solution was washed and dried as described in Example 1, and the lowboiling fraction was distilled off (0.2 mm.; temperature,

below 180 C.). There were obtained 25.4 parts of a viscous, pale yellow liquid of III as the distillation residue. n 1.4760.

Saponification value: Found, 189.5; calculated, 190.5.

Acid value: Found, 1.2; calculated, 0.

Acetyl value: Found, 3.8; calculated, 0.

Analysis.Found; C, 77.7; H, 9.44%. Calculated for C3gH3gO4; C, H,

IR spectrum (liquid film, cm.-

1735 (s): 11 ester 1250 (In), 1135 (m): v ester 720 (m): -(CH polymethylene (lauryl).

NMR spectrum (CCI, solution, TMS as internal standard, r)!

6.00 (t, J=5 Hz., 4H):

7.98 (undissolved resonance, 6H): adamantane tertiary H and Ari-21000- 8.28.6 (undissolved resonance) :adamnntane 52H secondary H 9.74 (s) EXAMPLE 4 Preparation of 1,3-bis(stearyloxycarbonylmethyl) adamantane (IV) In the same apparatus used in Example 1, a mixture of 12.6 parts of 1,3 bis(carboxymethyl)adamantane, 29 .7 parts of stearyl alcohol, 0.13 part of stannous oxide, and 9 parts by volume of xylene was refluxed with stirring for 7 hours while the reaction temperature was kept between 210 and 220 C. The volume of the water distilled off toward the end of the reaction was 2.0 parts by volume. Then after adding 100 parts by volume of xylene to the reaction mixture, the xylene solution was washed and dried as described in Example 1, and the low-boiling fraction was distilled off from the xylene solution under a reduced pressure (0.1 mm. Hg; temperature, below 180 C.). The distillation residue solidified when cooled. The crude product was recrystallized from acetone containing a small amount of ligroin to give 36.4 parts of colorless kneedles of pure IV (the yield=96% m.p. 4444.8 C.

Saponification value: Found, 147.1; calculated, 148.7.

Acid value: Found, 0.0; calculated, 0.

Acetyl value: Found, 0.30; calculated, 0.

Analysis.Found: C, 79.6; H, 12.1%. Calculated for C50H920'4: C, H,

IR spectrum (KBr, GEL-1):

1735 (s): v ester 1250 (m), 1130 (in): v,. ester 725 (m): p(CH polymethylene (stearyl).

NMR spectrum (CCL, solution, TMS as internal standard, 1):

6.01 (t, 1:5 Hz., 4H):

-CO OCH:-

7.97 (undissolved resonance, 6H): adamantane tertiary H and rid-@ 000- 6 8.42 (undissolved resonance) (76H) zi gifi gg i (s) :akylmethylene H 9.12 (t, 1:5 Hz., 6H):

The mass spectrum of IV could not be measured because of its low volatility.

EXAMPLE 5 Preparation of 1,3-bis(oleyloxycarbonylmethyl) adamantane (V) By the same procedure as described in Example 3, a mixture of 12.6 parts of 1,3-bis(carboxymethyl)adamantane, 29.5 parts of oleyl alcohol (purity, 78% 0.13 part of zinc oxide and 9.0 parts by volume of xylene was refluxed for 6 hours at a temperature between 210 and 220 C. After xylene was added, followed by washing, drying and distilling, the reaction mixture gave 35.4 parts of the diester mainly consisting of V. The product was a pale yellow liquid with m, 1.4818.

Saponification value: Found, 149.1; calculated, 148.9.

Acid value: Found, 0.31; calculated, 0.

Acetyl value: Found, 2.5; calculated, 0.

Analysis.-Found C, 79.73; H, 10.1%. Calculated for 05 11 3304: C, 79.73; H,

EXAMPLE 6 Preparation of 1,3-bis(cyclohexyloxycarbonylmethyl) adamantane (VI) 1730 (s): 11 ester 1260 (s), 1140 (s): v ester.

NMR spectrum (CCl, solution, TMS as internal stand ard, 1'):

5.30 (broad s, 2H):

8.00 (s, 6H): adamantane tertiary H and xa-qr coo- 8.1-9.2 (complex m, H): adamantane secondary H and cyclohexyl H.

Mass spectrum (m/e, relative intensity): 416 (1.1) (parent peak), 335 (1.5), 334 (1.8), 317 (2.0), 275 (118), 253 (51.8), 252 (12.9), 235 (34.9), 234 (22.0), 206 (31.9), 193 (100.0), 175 (4.8), 147 (9.0).

EXAMPLE 7 Preparation of 1,3-bis(exo-trimethylenenorbonyl-(2)- exooxycarbonylmethyl)adamantane (VII) By the same procedure as described in Example 3, a mixture of 28.2 parts of 1,3-bis(carboxymethyl)adamantane, 37.2 parts of 2-exo-hydroxy-exo-trimethylenenorbornane, 0.2 part of zinc oxide and 8.0 parts by volume of xylene was refluxed for 6 hours at a temperature between 215 and 225 C. The resulting reaction mixture was treated to give 46.4 parts of an almost colorless, viscous liquid of VII (the yield=%) as the distillation residue.

3,849,473 I 7 8 n 1.5323. --1; .Acompound of the formula Saponification value: Found, 2135; calculated,- 215.5. Acid value: Found, 1.4; calculated, 0. Acetyl value: Found, 0.37; calculated, 0. Analysis.-Found: C, 78.5; H, 9.2%. Calculated for ,11, 0 c, 78.42; H, 9.29%. R 5 1 (:11 com 2 IR spectrum (liquid film, cmr

4 1730 c=oa ester cu (200R 1255 m), 1130 (m): 11 ester; 2

- wherein NMR spectrum (CCl; solution, I MS as internal stand- R is selected from the group consisting of crotyl, oleyl, ard, r): linoleyl and methallyl, and

v R is H or alkyl having 1 to 4 carbon atoms. 5.3-5.6 (undissolved resonance, 2H): :2, A compound of the formula p v I a 5 1 cu cooa -Q v 1 5 4 E Y I cs cook wherein g R is selected from the group consisting of cyclohexyl, methylcyclohexyl, hexahydrobenzyl, cyclohexeny], p 111, Peaks at 843, -9 (4&1) decalyl, adamantyl, exo-trimethylene norbornyl and 7.96 (s) 2,3-dihydro-exo-dicyclopentadienyl, and

where the peak at 7.96 (s) belongs to adamantane R is H or alkyl having 1 to 4 carbon atoms. tertiary H and References Cited g UNITED STATES PATENTS 3,328,434 6/1967 Hamilton 260-4109 I 3,700,726 10/1972 Johnson, Jr. et al. 260491 the rest are assigned (0 the other PO YCYCIIQ H. r 3 342 0 9/ 9 7 R- inh 2 0 48 Mass spectrum (m/e): 520 (parent peak), 3361363,: OTHER REFERENCES Accurate intensities of the spectrum could notlbe meas ured because of the low volatility of VII.

The embodiments of the invention in which an elusive property or privilege is claimed are l defined as I follows: H I Y 2:52-56R'. 56. S

Briggs at 51.; Tet. Letters, 1968, 1097.

RO BEIQT GERSTL, Primary Examiner US. Cl. XLR. 

1. A COMPOUND OF THE FORMULA 